Should you worry? YES!! It's a wake-up call. You could end up having those sounds in your head permanently if you don't do something now to reduce the noise load on your ears. Tinnitus is a well-known by-product of loud amplified stage performances, and once it sets in (i.e. becomes nerve-degeneration) you will live with it for life. It's the sound-equivalent of what working in cigarette-smoky atmospheres does for your lungs.

The other musicians in the band run the same risks, whether they realise it or not, so get them to turn the volume down. A retired rock musician I know told me he used to use high-density foam ear-plugs during his gigs for this very reason, though all he had to do was play an instrument. Calling or singing is more tricky because of the necessary vocal feedback. Do some research on the net, and do something about this please!